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May Weather in Charleston, United States

Last updated: June 24, 2025

In May, the average temperature in Charleston, United States hovers around 17°C (63°F). Temperatures can range from a chilly 2°C (37°F) at the lowest to a warm 32°C (90°F) at the highest. With an average humidity level of 69%, you can expect a reasonably damp atmosphere. Overall, the region experiences 118 mm (4.6 in) of precipitation spread over approximately 12 days throughout the month.

May Temperature in Charleston

In May in Charleston, the average temperature is 17°C (63°F). Maximums can reach 32°C (90°F), while minimums can drop as low as 2°C (37°F). Be prepared for a range of temperatures when traveling to Charleston during this month.

May Weather in Charleston: Daily Temperature Highs, Lows, and Averages

The chart illustrates May temperature patterns in Charleston, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Charleston, May typically has an average temperature of 17°C (63°F), with highs reaching up to 32°C (90°F) and lows dropping to around 2°C (37°F).
JanFebMarAprMayJunJulAugSepOctNovDec343743536372787670614639
Data source: Temperature data for Charleston generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

May Precipitation in Charleston

In Charleston in May, the precipitation amount is 118 mm (4.6 in) spread over 12 days.

May Precipitation Trends in Charleston

The chart displays monthly precipitation patterns in Charleston, with values for each month alongside May’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how May’s conditions compare to those of other months. In Charleston, May typically receives around 118 mm (4.6 inches) of precipitation spread over approximately 12 days.
JanFebMarAprMayJunJulAugSepOctNovDec66107103111118941441269113082102
Data source: Precipitation data for May generated using information from the Copernicus Climate Change Service.
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May Humidity in Charleston

In Charleston in May, humidity is 69%. With an average temperature of 17°C (63°F), this humidity feels like a warm embrace, making outdoor activities feel slightly heavier, yet still comfortable for exploring.

May Average Humidity in Charleston

This chart illustrates the average monthly humidity levels in Charleston, with May’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In May, average humidity in Charleston is approximately 69%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%82%81%78%70%69%62%65%68%74%82%80%
Data source: Humidity data for May generated using information from the Copernicus Climate Change Service.

May UV Index in Charleston

In Charleston in May, the maximum UV index reaches 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. For more detailed information, you can check the Hourly UV Index in Charleston.

Maximum UV Index Levels in Charleston for May

The chart shows the monthly maximum UV Index (UVI) for Charleston in May, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In May, the maximum UV index in Charleston typically reaches 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec356810101098642
Data source: Charleston May UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

How May Weather in Charleston Compares to Other Months

Weather in Charleston varies notably across the year, with each month offering distinct climate conditions. This page compares May’s weather to other months in Charleston, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Charleston, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather1°C (35°F)66 mm (2.6 inches)84%moderate
February Weather3°C (37°F)107 mm (4.2 inches)82%moderate
March Weather6°C (43°F)103 mm (4.0 inches)81%high
April Weather12°C (53°F)111 mm (4.4 inches)78%very high
May Weather17°C (63°F)118 mm (4.6 inches)69%very high
June Weather22°C (73°F)94 mm (3.7 inches)69%very high
July Weather26°C (79°F)144 mm (5.6 inches)62%very high
August Weather25°C (77°F)126 mm (5.0 inches)65%very high
September Weather21°C (71°F)91 mm (3.6 inches)68%very high
October Weather16°C (61°F)130 mm (5.1 inches)74%high
November Weather8°C (47°F)82 mm (3.2 inches)82%moderate
December Weather4°C (39°F)102 mm (4.0 inches)80%low

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